Traditionally, all sanitary napkins have suffered from "distortion failures". These failures because napkins are generally not 3-dimensionally shaped and made to continuously dynamically conform to the perineal area of the wearer particularly when the wearer is in motion. Generally the torque forces exerted on the side of the napkin distort the discharge target area on the face of the napkin and may provide a substantial number of napkin failures due to the angle at which menses strikes the distorted surface.
One of the ways to overcome this type of failure, which has so far proven to be commercially unsuccessful has been to add a positioning means to a conventionally constructed sanitary napkin. This positioning means provides a 3-dimensional napkin profile, is absorbent, and is designed to engage the labia. U.S. Pat. No. 3,528,422 is an example of a sanitary napkin with a raised portion designed to engage the labia.
It is felt that in order to design a satisfactory sanitary napkin with an interlabial pad attached, the interlabial component should be moveable with respect to the conventional napkin absorbent layer. This is true because as forces are exerted on the conventional absorbent layer which would tend to distort them, the interlabial portion will remain in place and functioning therefore minimizing the ultimate effects of these distortion forces. U.S. Pat. Nos. 3,183,909; 3,406,689; and 4,340,058 describe napkins which can be thought of as including an interlabial portion which is moveable with respect to the other absorbent components. Each of these patents disclose an absorbent element which forms the interlabial component as a separate element. This means that in each instance the manufacture of these napkins involve the added steps of assembling the various components and positioning them in registry, both of which make the cost of manufacturing such a high volume disposable product too high.
U.S. Pat. No. 4,182,334 discloses a sanitary appliance shaped somewhat like a paper airplane which is designed to be partially moveable with respect to body movement although this appliance which is essentially of unitary construction does not include an interlabial component.